The field of the invention relates generally to any type of turbine, and more specifically, to a method and a system for sealing a gap between a turbine bucket dovetail and a turbine rotor using a deformable locking seal.
Gas turbines generally include a turbine rotor (wheel) with a number of circumferentially spaced buckets (blades). The buckets generally may include an airfoil, a platform, a shank, a dovetail, and other elements. The dovetail of each bucket is positioned within the turbine rotor and secured therein. The airfoils project into the hot gas path so as to convert the kinetic energy of the gas into rotational mechanical energy. A number of cooling medium passages may extend radially through the bucket to direct an inward and/or an outward flow of the cooling medium therethrough.
Leaks may develop in the coolant supply circuit based upon a gap between the tabs of the dovetails and the surface of the rotor due to increases in thermal and/or centrifugal loads. Air losses from the bucket supply circuit into the wheel space may be significant with respect to blade cooling medium flow requirements. Moreover, the air may be extracted from later compressor stages such that the penalty on energy output and overall efficiency may be significant during engine operation.
Efforts have been made to limit this leak. However, though the known seals may seal the gap well and may be durable, the known seals cannot be easily disassembled and replaced in the field.